ok i had my whole sysyem ordered online incl the box and sub, but now the sub order never went thru and i decided on a diff sub instead
this new sub will need a smaller box than the one i ordered so is there any way to get my 1.31 cu ft box down to around .9 cu ft
i dont really want to get a new one and have this one sittin in my basement as a waste of my money

 

If it's sealed, calculate the displacement and throw a properly sized block of wood in there to decrease airspace.

 

Make sure you screw down that block so it won't hit or make noise while you drive.